A Brazilian presidential candidate was killed today. His plane went down as he was traveling to a campaign event. 49-year-old Eduardo Campos was running third in the polls. The election is October fifth. Brazil's president, Dilma Rousseff, has declared three days of official mourning. The candidate's death has made a hotly contested election even more uncertain. That story from NPR's Lourdes Garcia-Navarro in Sao Paulo.

LOURDES GARCIA-NAVARRO, BYLINE: Campos's plane was flying in bad weather and heavy rain, and it went down in a residential neighborhood in the coastal city of Santos damaging several buildings. He was killed along with everyone else on board. Campos was a former governor of the northeastern state of Pernambuco, and he was once an ally of President Dilma Rousseff, but he broke with her and decided to run for president on a more business-friendly leftist platform. The news has sent political shockwaves through the country.

JOAO CLEMENTE: (Singing in foreign language).

GARCIA-NAVARRO: Joao Clemente from Mackenzie University says Campos's sudden-death is a political tsunami that makes the presidential race unpredictable. Campos was unlikely to face Dilma Rousseff in a runoff, but his running mate is Marina Silva. She was always seen as the bigger threat to Rousseff. When she was unable to form her own party, Silva decided to run on Campos's ticket. The big question now is whether the Campos coalition will choose her to succeed him.

PEDRO ARRUDA: (Portuguese spoken).

GARCIA-NAVARRO: Pedro Arruda is a political scientist at the Pontifical Catholic University of Sao Paulo. Marina Silva is very popular in Brazil he says. In the last presidential elections, she got almost 20 million votes. As a leftist and a female, her candidacy, he says, would most likely take away votes from Rousseff, and it may even mean that she enters the final runoff round instead of the man who is running second in the polls right now, right-of-center Aecio Neves. But Arruda cautions that it's still too early to tell what will happen. Eduardo Campos is survived by his wife and five children. Lourdes Garcia-Navarro, NPR News, Sao Paulo. Transcript provided by NPR, Copyright NPR.